Commit 514df14f authored by John Garry's avatar John Garry Committed by Darrick J. Wong
Browse files

xfs: refactor xfs_reflink_end_cow_extent() 



Refactor xfs_reflink_end_cow_extent() into separate parts which process
the CoW range and commit the transaction.

This refactoring will be used in future for when it is required to commit
a range of extents as a single transaction, similar to how it was done
pre-commit d6f215f3.

Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
parent 6baf4cc4

fs/xfs/xfs_reflink.c

+42 −30
Original line number Diff line number Diff line
@@ -786,35 +786,19 @@ xfs_reflink_update_quota( 
 * requirements as low as possible.

 */

STATIC int

xfs_reflink_end_cow_extent(

xfs_reflink_end_cow_extent_locked(

	struct xfs_trans	*tp,

	struct xfs_inode	*ip,

	xfs_fileoff_t		*offset_fsb,

	xfs_fileoff_t		end_fsb)

{

	struct xfs_iext_cursor	icur;

	struct xfs_bmbt_irec	got, del, data;

	struct xfs_mount	*mp = ip->i_mount;

	struct xfs_trans	*tp;

	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, XFS_COW_FORK);

	unsigned int		resblks;

	int			nmaps;

	bool			isrt = XFS_IS_REALTIME_INODE(ip);

	int			error;



	resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,

			XFS_TRANS_RESERVE, &tp);

	if (error)

		return error;



	/*

	 * Lock the inode.  We have to ijoin without automatic unlock because

	 * the lead transaction is the refcountbt record deletion; the data

	 * fork update follows as a deferred log item.

	 */

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);



	/*

	 * In case of racing, overlapping AIO writes no COW extents might be

	 * left by the time I/O completes for the loser of the race.  In that
@@ -823,7 +807,7 @@ xfs_reflink_end_cow_extent( 
	if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) ||

	    got.br_startoff >= end_fsb) {

		*offset_fsb = end_fsb;

		goto out_cancel;

		return 0;

	}



	/*
@@ -837,7 +821,7 @@ xfs_reflink_end_cow_extent( 
		if (!xfs_iext_next_extent(ifp, &icur, &got) ||

		    got.br_startoff >= end_fsb) {

			*offset_fsb = end_fsb;

			goto out_cancel;

			return 0;

		}

	}

	del = got;
@@ -846,14 +830,14 @@ xfs_reflink_end_cow_extent( 
	error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK,

			XFS_IEXT_REFLINK_END_COW_CNT);

	if (error)

		goto out_cancel;

		return error;



	/* Grab the corresponding mapping in the data fork. */

	nmaps = 1;

	error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data,

			&nmaps, 0);

	if (error)

		goto out_cancel;

		return error;



	/* We can only remap the smaller of the two extent sizes. */

	data.br_blockcount = min(data.br_blockcount, del.br_blockcount);
@@ -882,7 +866,7 @@ xfs_reflink_end_cow_extent( 
		error = xfs_bunmapi(NULL, ip, data.br_startoff,

				data.br_blockcount, 0, 1, &done);

		if (error)

			goto out_cancel;

			return error;

		ASSERT(done);

	}
@@ -899,17 +883,45 @@ xfs_reflink_end_cow_extent( 
	/* Remove the mapping from the CoW fork. */

	xfs_bmap_del_extent_cow(ip, &icur, &got, &del);



	error = xfs_trans_commit(tp);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	if (error)

		return error;



	/* Update the caller about how much progress we made. */

	*offset_fsb = del.br_startoff + del.br_blockcount;

	return 0;

}



out_cancel:

/*

 * Remap part of the CoW fork into the data fork.

 *

 * We aim to remap the range starting at @offset_fsb and ending at @end_fsb

 * into the data fork; this function will remap what it can (at the end of the

 * range) and update @end_fsb appropriately.  Each remap gets its own

 * transaction because we can end up merging and splitting bmbt blocks for

 * every remap operation and we'd like to keep the block reservation

 * requirements as low as possible.

 */

STATIC int

xfs_reflink_end_cow_extent(

	struct xfs_inode	*ip,

	xfs_fileoff_t		*offset_fsb,

	xfs_fileoff_t		end_fsb)

{

	struct xfs_mount	*mp = ip->i_mount;

	struct xfs_trans	*tp;

	unsigned int		resblks;

	int			error;



	resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,

			XFS_TRANS_RESERVE, &tp);

	if (error)

		return error;

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	xfs_trans_ijoin(tp, ip, 0);



	error = xfs_reflink_end_cow_extent_locked(tp, ip, offset_fsb, end_fsb);

	if (error)

		xfs_trans_cancel(tp);

	else

		error = xfs_trans_commit(tp);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	return error;

}